1. Field of the Invention
The present invention generally concerns methods of forming electrostatically charged gelatin. More specifically, the invention pertains to methods whereby gelatin is extracted from a collagen-containing raw material and processed so as to produce a gelatin product exhibiting an overall positive or negative electrostatic charge based upon the particular processing conditions employed.
2. Description of the Prior Art
Gelatin is a transparent, brittle, essentially odorless and tasteless powder. Gelatin is typically extracted from by-products of the meat industry including pork skin, tendons, ligaments, and bones. Gelatin has been utilized in numerous applications because of its ability to absorb 5-10 times its own weight in water and to form a gel in solutions having temperatures of about 35-40° F. and below. Gelatin has been used in the manufacture of rubber substitutes, adhesives, cements, lithographic and printing inks, plastic compounds, artificial silk, photographic plates and films, matches, light filters for mercury lamps, clarifying agents, hectographic masters, sizing paper, and textiles. The pharmaceutical industry has utilized gelatin as a suspending agent, an encapsulating agent, a tablet binder, and a coating agent.
Gelatin has been used in the food industry as a thickener, a food stabilizer and a food texture enhancer. However, the use of gelatin in the pet food industry has been rare due in part to its expense and the availability of less costly viscosity enhancing agents such as gums derived from plant and vegetable sources. Generally, in food industry applications, gelatin exhibits no net electrostatic charge. The conventional method of extracting food-grade gelatin includes adjusting the pH of the gelatin-containing aqueous dispersion to the isoelectric point of the gelatin. The isoelectric point is the pH at which a material exhibits no net electrostatic charge.
In some food-related applications, it may be desirable to use electrostatically charged gelatin. For example, gelatin having a negative electrostatic charge may be incorporated into hairball-prevention pet food products. In the formation of a hairball, the hair ingested by the animal clings to the lining of the stomach where it becomes entangled with other hairs and undigested food. Hairballs can be very problematic for the animal in that hairballs can lead to diarrhea and vomiting. If the animal were to ingest gelatin having a negative electrostatic charge, the gelatin would attract the hair inside the stomach of the animal and carry it through the animal's digestive system thereby preventing hairball formation.
U.S. Pat. No. 2,398,004 teaches a method of controlling the isoelectric point of gelatin for use in photographic applications. The isoelectric point of the gelatin may be altered by the addition of an alkali to increase the pH of the gelatin solution. This pH is maintained for a period of time and subsequently, the action of the alkali is stopped by the addition of an acid.
U.S. Pat. No. 2,514,635 discloses a method of reducing the viscosity of gelatin, especially photographic gelatin. The method uses an amine and amine salt buffer to raise the pH of the gelatin solution in order to increase the gelatin viscosity.
No method of manufacturing gelatin has thus far been available which would enable the gelatin to assume an electrostatic charge. Therefore, there exists a real and unfulfilled need for a method of producing gelatin having an electrostatic charge and being of food-grade quality.